Alfa Romeo Owners Club of Australia Forum

Technical => 116 Series (Alfetta Sedan/GT/GTV & Giulietta Sedan) => Topic started by: Alfetta77 on July 18, 2018, 08:18:13 PM

Title: Unusual Nut for Headlight Screw
Post by: Alfetta77 on July 18, 2018, 08:18:13 PM
Hi, at the rear of my grilles there is an unusual looking nut that the headlight screw fits into (see large-scale photo). On the other headlight there is a normal-looking nut and washer (bottom right of the other photo). My questions are should both sides have the unusual looking nut?, and if so, where might I get hold of one?
Title: Re: Unusual Nut for Headlight Screw
Post by: Alfetta77 on August 19, 2018, 07:28:24 PM
Googled some markings on the nut and found it is a Jack Nut, available from a couple of suppliers, Aerobolt http://aerobolt.com.au/products/threaded-inserts/jack-nut and Concept Fasteners https://www.conceptfasteners.com.au/shop/item/jk-nuts-insert. One less puzzle to solve... :)
Title: Re: Unusual Nut for Headlight Screw
Post by: Alfetta77 on August 21, 2018, 08:43:08 PM
Spoke too soon - bought some M4 Jack Nuts, and the screw doesn't fit  :( - so off to Supercheap to buy a thread pitch gauge...
Title: Re: Unusual Nut for Headlight Screw
Post by: Citroƫnbender on August 21, 2018, 08:51:03 PM
That's a disappointment. Can't measure the thread with calipers?

(I'm assuming it's not an interference thread.)
Title: Re: Unusual Nut for Headlight Screw
Post by: bonno on August 21, 2018, 09:17:08 PM
My guess is that it is the fine pitch M4 x 0.5 bolt and you have been supplied the M4 x 0.7 course pitch jack nut/rivet nut. Refer to link for pitch size
https://www.google.com.au/search?sourceid=navclient&ie=UTF-8&rlz=1T4MXGB_enAU573AU573&q=m4+thread+pitch
Title: Re: Unusual Nut for Headlight Screw
Post by: Alfetta77 on August 21, 2018, 09:29:28 PM
Thanks for the replies - fine pitch would make sense, will check with a gauge to make sure. I don't have calipers, probably should invest in a set!
Title: Re: Unusual Nut for Headlight Screw
Post by: Alfetta77 on August 26, 2018, 09:56:52 PM
Checked with the pitch gauge, seems to be 0.7...and yet the M4x0.7 nut doesn't fit! Will try nuts from another supplier. Any other thoughts / ideas welcome!
Title: Re: Unusual Nut for Headlight Screw
Post by: Citroƫnbender on August 26, 2018, 10:48:51 PM
Is the screw correct, or has it been swapped for a 5/32"?
Title: Re: Unusual Nut for Headlight Screw
Post by: Alfetta77 on August 27, 2018, 09:29:49 AM
It is an original screw, so should be metric? I will try both metric and imperial with the thread checker at Bunnings and see what I come up with.